mmc: sdhci: Use timer based timeout detection in sdhci_send_command()

The loop counter based timeout detection does not work on the Armada
38x based board (DB-88F6820-GP). At least with dcache enabled a
timeout is detected. Without dcache enabled, the timeout does not
occur. Increasing the loop counter solves this issue. But a better
solution is to use a timer based timeout detection instead. This
patch now implements this timer based detection.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Pantelis Antoniou <panto@antoniou-consulting.com>
Cc: Luka Perkov <luka.perkov@sartura.hr>

drivers/mmc/sdhci.c

@@ -133,8 +133,8 @@ static int sdhci_send_command(struct mmc *mmc, struct mmc_cmd *cmd,
 	int trans_bytes = 0, is_aligned = 1;
 	u32 mask, flags, mode;
 	unsigned int time = 0, start_addr = 0;
-	unsigned int retry = 10000;
 	int mmc_dev = mmc->block_dev.dev;
+	unsigned start = get_timer(0);
 
 	/* Timeout unit - ms */
 	static unsigned int cmd_timeout = CONFIG_SDHCI_CMD_DEFAULT_TIMEOUT;
@@ -222,15 +222,15 @@ static int sdhci_send_command(struct mmc *mmc, struct mmc_cmd *cmd,
 	flush_cache(start_addr, trans_bytes);
 #endif
 	sdhci_writew(host, SDHCI_MAKE_CMD(cmd->cmdidx, flags), SDHCI_COMMAND);
+	start = get_timer(0);
 	do {
 		stat = sdhci_readl(host, SDHCI_INT_STATUS);
 		if (stat & SDHCI_INT_ERROR)
 			break;
-		if (--retry == 0)
-			break;
-	} while ((stat & mask) != mask);
+	} while (((stat & mask) != mask) &&
+		 (get_timer(start) < CONFIG_SDHCI_CMD_DEFAULT_TIMEOUT));
 
-	if (retry == 0) {
+	if (get_timer(start) >= CONFIG_SDHCI_CMD_DEFAULT_TIMEOUT) {
 		if (host->quirks & SDHCI_QUIRK_BROKEN_R1B)
 			return 0;
 		else {